Wireless Access points with External antenna

DevilWAH

Hi,

I am going to be installing wireless in to a high bio-security building. With in the building areas are broken down in to Suites, each suite is a encased in 200mm double reinforced concrete and with in each Suite it is divided in to 3 areas using the same concrete walls and Steel air tight doors. So wireless will not travel between the areas

The total size of the suite is only about 15 meter square, with a 10 X 10 meter main room and then two small 4X4 meter rooms on the end. (imagen a soccer field 15 meters long, with the top third walled of and divided in to 2)

Because we cant put access points in the room (the get fumigated with nasty stuff and sprayed down with nasty chemicals) the access point will be out side the room and an antenna installed inside.

My questions is, if I had a single Access point such as a CISCO 3600e that supports 3 antennas, would it work to put one in each of the rooms? or do all antennas need to be able to "see" each other. There is only going to be one or two devices in each suite that will move between the areas, so having to dedicate an AP to each area is expensive and unefficent.

Any one had much dealing with external Antennas ?

NightShade1

No, don t do that
The multiple antenna is for multiple stream data and for diversity as well...
This just wont work well.

Check out also hwo many devices will be connecting in each room, how much BW each device need etc etc.

You need to design the Wifi properly in order to make it work properly, otherwise it wont work as expected and this is why people does not trust wifi when we all should

Cheers
Carlos

DevilWAH

I know there for multiply data streams, but not working well, not deployed by the book and not working are different things.

yes you lose any MIMO benefit separating the antennas, but in this case as I mentioned we are looking at a single user per Suite, so thats a single user per access point. Its low BW applications and not looking for any Location tracking. Also each room / Suite is a sealed unit as far as wireless goes so no worrying about overlap from neighboring AP.

Deploying wireless to 200 rooms of which at any one time 50%+ will be empty and even when they are occupied wireless usage will be minimal, putting a separate access point in to each room become very efficient. Also considering putting a penetration in to a room is an extremely costly process (talking several thousand pounds per penetration, one you included the cost to seal and pressure test it all), we unfortunately are in a situation that no wireless manufacture caters for it being so niche.

I suppose the question is, does separating the antennas on a MIMO access point simple result in SISO operation?

NightShade1

They are not supposed to work that way, like I said it just wont work properly.

First:
You will have the hidden node issue. Which is that clients in one room will not able to hear clients in another room(in your case). So they will attempt to transmit at the same time thinking the channel is clear when its not, so you will see a lot of collisions which lead to a bad performance
Remember that in wireless just one device can access the medium... if 2 or more try to access it at the same time there are collisions.

Second:
You will loose MIMO Benefits which are good. Even if your clients are SISO, the AP still operate in MIMO so it improve your Rx signal which improve the signal reliability through obstructions.

Third but not least
Any vendor(Cisco, Aruba Ruckus) would never recommend this design. The correct design for you would be one AP per Room. So I guess you could get those low density APs

Im not a cisco wifi partner so I cannot recommend you a model for it
For example in Aruba there are 4 indoor with external antennas option and the price range vary from 395 to 1295. I suppose Cisco got something like this???

Cheers
Carlos

netsysllc

Ubiquiti or Mikrotik would be your best options. they make low priced high quality access points and you would be able to use one per room. Something like RocketM2-US - 802.11N MIMO 2.4 GHz Rocket AP USA

xnx

Ask on reddit.com/r/networking, some very experienced people on there

JDMurray

The wireless networking crowd sourcing at dslreports.com is much better.